I have a problem with my sony reader pr-500. The LCD don't work very well, because the contrast of LCD is wrong. Tomorrow I will send a photo of LCD.

The contrast on my Reader was such that I had a lot of problems with ghosting (visible remnants of previous screen images, even remaining on the screen after two or three page flips).

I sent it in to Sony for repair. The technician tried adjusting the setting to its lowest value so as to reduce the ghosting, but that didn't work. He ordered a new e-Ink screen for it, and that new screen works much better. I'm glad I sent it in.

Better to send it in. But I'm wondering if the resistor just isn't able to turn far enough. When I tried messing with the resistor, there was only a one-eigth-turn worth of slack in the decrease-the-contrast (clockwise) direction. So like I said, you should send it in. But if you've put blinking leds and spinning rims on your Reader and can't send it to Sony, I think maybe replacing that variable resistor with another would do the trick.

... I think maybe replacing that variable resistor with another would do the trick.

Maybe so. It depends on which end of the post (potentiometer -- AKA variable resistor for the non-electronics geeks) that "not enough slack" is on: the more resistance or the less resistance. If it was closer to the "less" end, then you're not likely to get any more out of a replacement, because the bottom of a pot's resistance is 0 ohms (unless the pot is defective, and doesn't get all the way there, of course). If you were closer to the top, then yeah, adding another, larger one might get you some more performance.

Before anyone starts in on replacing the thing, they should be aware that soldiering by hand on surface contact circuit boards is an ... interesting undertaking, and can be rather difficult to pull off.

I saw the battery information link posted on these forums [copied below], but can someone please be a little more specific of where to buy a spare battery in the USA..? Like one of those IPOD repair places perhaps..?

This is a photo of the LCD. I opened the Reader, and I adjasted the contrast, but there wasn't any effect.

Sorry to be picky, but this is not a liquid crystal display. Please don't call it an LCD. To me, calling this an LCD display is very derogatory Call it "the display" or "the e-ink panel" perhaps. The display is what makes this device so good

The Built-in rechargeable battery in PRS-500 LIS1356HNPAQ (LITHIUM ION STORAGE BATTERY ASSY) is DC IN 3.7 V, and its code (for original battery replacement from Sony for $82.12 at servicesales.sel.sony.com) is X-2149-315-1. This partnumber does not appear on the battery itself, only in the Service Manual. A replacement (size and mAh) should be indicated by someone, as original parts are too expensive. This battery is probably 850mAh as indicated here http://www.pricerunner.fr/f/462/Acce...a_marques=sony.

The Battery is not connected to the main CPU but to a power control IC (a SN412005RHLR - the Sony IC responsible for supplying energy to the board, charging the battery, managing USB and AC power and Thermal Shutdown).

The Main-CPU is MC9328MXLVP20R2 - a Freescale Semiconductor i.MX Family applications processor with an ARM920T™ core that operates at 200 MHz. Integrated modules include a USB device, an LCD controller, and an MMC/SD host controller.
datasheet at http://www.freescale.com/files/32bit.../MC9328MXL.pdf
(There should be no ROM here)

In terms of internal memory the unit has 2x modules of 64MB SDRAMs (volatile memory for variables and program execution), 1x module of 2MB ROM (main bootloader/"bios" is probably here) and 1x module of 128MB ROM (where the "operational system" and books should be). So, when people say the PRS-500 has 64MB of free space for books they are considering what is left after applications.

To Enter TEST MODE one should insert a memory stick with the following files:
autorun.xml,
icon.png,
key.png,
lut.bin

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A change of the LUT (Look Up Table) is required when a INK INDICATOR ELEMENT, MAIN BOARD and FLASH ROM (IC1611) are replaced.

Vcom Voltage Adjustment - Vcom voltage for the display panel varies for each panel. Vcom adjustment is required when replacing a board or panel. To Adjust observe the negative side of C1666 on an oscilloscope, and use RV1601 to adjust the voltage that is generated when the screen is changed so that it satisfies the standard (oscilloscope at 500mV/DIV, 400 ms/DIV, must generate 1.3Vp-p between low and high).

Hmm where did you get service manual info from? I'd love to have a look at one... And if you have those test mode files it would be great to have a look too.
Dumping the main flash is not hard... on original firmware you could do it with my ebook.py script, with later ones you can run shell commands via autorun hook.